PROJECT SUMMARY Poor self-regulation interferes with individuals' engagement in health maintenance behaviors, including management of type 1 diabetes. However, it is not well understood if parents' self-regulation interferes with their children's engagement in health maintenance behaviors. This proposed supplement to 4UH3HD087979 seeks to expand the work of PIs Miller and Fredericks by providing an opportunity to examine the role of parents' self-regulation in glycemic control and treatment regimen adherence among pre-adolescents and adolescents with type 1 diabetes. While pre-adolescents and adolescents often desire increasing autonomy in their disease management, it is essential that parents remain closely involved by implementing diabetes- specific tasks and providing a low-conflict home environment that supports engagement in health behaviors such as regular physical activity. Poor self-regulation among parents may limit their capacity to provide such support and resources for their children. With the support of this supplement, the study team will: (1) add measures of parents' self-regulation, parent-reported youth SR, and diabetes-relevant family environment characteristics to the baseline assessment of PIs Miller and Frederick's clinical trial of adolescents who have poor type 1 diabetes regulation (N=94), and (2) recruit a new sample of parents of pre-adolescents and adolescents with type 1 diabetes and measure parents' self-regulation and the diabetes-relevant family environment among this sample (N=106). These data from a total sample of 200 mothers will be linked to measures of youth's current glycemic control and recent type 1 diabetes-related health events through the electronic health record, and with the detailed data on adolescents' treatment regimen adherence and health related quality of life collected via the UH3. Together, this information will be used to address the following specific aims: Aim 1. Examine associations between parents' SR and youth T1D outcomes, and Aim 2. Examine how parents' SR is related to key diabetes-relevant family environment characteristics known to support youth T1D treatment adherence and glycemic control. Through an exploratory aim, we will also examine whether parents' baseline self-regulation modifies the effect of the UH3's bundled intervention to improve adolescents' self-regulation on adolescents' treatment regimen adherence. Findings from this study will provide insight into the potential utility of targeting parents' self-regulation, alone or in concert with youth's self-regulation, as a means to improve the health and quality of life among youth with type 1 diabetes.